1. Field of the Invention
The present invention is directed to a valve for controlling a fluid (gas or liquid) flow, of the type having an admission and a discharge with a valve seat, a valve part displaceable relative to the valve seat, and a seal therebetween, whereby the valve part presses the seal against the valve seat in one position and thus interrupts the flow.
2. Description of the Prior Art
It is a well-known problem in conventional valves that the valve seat as well as the valve part have imperfections in the region of the surfaces to be sealed, or can be damaged in such a way that leakage can occur. After some time, an elastic seal or packing can also harden or deform, so that a valve that was initially functional becomes unusable over time. In the case of an apparatus wherein high precision in the dosing of a fluid is required, particularly when the valve should also allow extremely slight quantities to pass, it is of great importance that this valve seal well even after a longer service time.
One device whose valves must have an extremely high sealing power is an implantable medication dosing pump for insulin dosing, whereby the medication is to be administered in extremely small doses having a volume of approximately 1 .mu.l. Such a device that is provided with a conventional valve of the type initially described is disclosed in U.S. Pat. No. 4,883,467.